3461 Find The Minimum Area To Cover All Ones I

Find the Minimum Area to Cover All Ones I

You are given a 2D binary array grid. Find a rectangle with horizontal and vertical sides with the** smallest** area, such that all the 1’s in grid lie inside this rectangle.

Return the minimum possible area of the rectangle.

 

Example 1:

Input: grid = [[0,1,0],[1,0,1]]

Output: 6

Explanation:

The smallest rectangle has a height of 2 and a width of 3, so it has an area of 2 * 3 = 6.

Example 2:

Input: grid = [[1,0],[0,0]]

Output: 1

Explanation:

The smallest rectangle has both height and width 1, so its area is 1 * 1 = 1.

 

Constraints:

1 <= grid.length, grid[i].length <= 1000
grid[i][j] is either 0 or 1.
The input is generated such that there is at least one 1 in grid.

class Solution:
    def minimumArea(self, grid: List[List[int]]) -> int:
        """
        traverse rows and find first row with 1 and last row with 1
        and same with col
        multiply

        """
        first_row = 10000
        last_row = 0
        first_col = 10000
        last_col = 0

        for i,k in enumerate(grid):
            #print(k)
            for j,l in enumerate(k):
                if l == 1:
                    first_row = min(first_row, i)
                    last_row = max(last_row, i)
                    first_col = min(first_col, j)
                    last_col = max(last_col, j)
        
        return (last_row- first_row + 1) * (last_col - first_col + 1)